Dull pain @ 18 weeks

Maja

FTM. I started feeling this strange pressing dull pain and heaviness in my lower abdomen at 18w5d now. I feel it on and off while peeing and sometimes while walking. Mostly it feels like heaviness or pressure. I also feel the baby movements quite often on both of my sides. Do you think this may be due to those moevemnts, my uterus growing or anything else?